With development of the display technology, a demand on display image quality is increasing. Also a demand on flat display devices with high image quality and high resolution is popular, and display panel manufacturers pay more and more attention hereto.
An existing pixel structure of an organic electroluminescence display panel for transparent display comprises a display area and a transparent area. Also the pixel structure comprises a pixel circuit which includes a thin film transistor, a storage capacitor and an organic electroluminescence device. The thin film transistor, storage capacitor and organic electroluminescence device are all arranged in the display area. In the case where a size of a display panel is fixed, the bigger the display area is, the smaller the transparent area is. In the existing organic electroluminescence display panel, a first polar plate and a second polar plate of the storage capacitor are usually formed respectively together with an active layer and a gate of the thin film transistor in the same patterning process with the same material, which means that the place where the storage capacitor is formed is non-transparent.
The pixel circuit structure in the organic electroluminescence display panel is more complex than that of a Liquid Crystal Display (LCD). It usually includes a plurality of thin film transistors and capacitors, which requires a larger display area to arrange electronic elements of the pixel circuit structure and thus results in the larger pixel size. Therefore, the existing organic electroluminescence display panel for transparent display has lower resolution, and the increase of the display area would decrease the transparent area so that the whole transparency of the display panel is low.
The inventors found in the prior art that, as the first and second polar plates of the storage capacitor are made of the same non-transparent materials respectively as the active layer and the gate, the first and second polar plates of the storage capacitor are both non-transparent, which impacts the transparency of the display panel. Moreover the storage capacitor arranged in the display area would result in the excessive pixel size and cannot achieve the transparent display with high resolution.